There has been developed heretofore a technology in which if it is determined that it is not possible to achieve deceleration of the driver's own vehicle to avoid a collision with an obstacle, the course of the driver's own vehicle is changed (see, for example, Patent Document 1). This technology enables the driver's own vehicle to avoid a collision with the obstacle. However, if another vehicle is running diagonally behind the driver's own vehicle, there is a possibility that the change in the course will cause the driver's own vehicle to enter the course of the vehicle behind.
As a countermeasure to this, there has also been developed a technology pertaining to a steering control apparatus that causes the driver's own vehicle to change the lane in which it travels in order to avoid a collision with a vehicle ahead of the driver's own vehicle, in which if a vehicle traveling behind in the lane in which the driver's own vehicle is to travel after the lane change is detected and there is a possibility that the driver's own vehicle will collide with the vehicle behind, the lane change is forbidden (see, for example, Patent Document 2).